The biggest kidney stone on record weighed more than a kilogram and was 17 centimeters in diameter. The patient didn't actually swallow a stone the size of a coconut. Kidney stones form inside the body, but unfortunately, they're extremely painful to get out. Stones Formation in Kidneys- A kidney stone is a hard mass of crystals that can form in the kidneys, ureters, bladder, or urethra . Urine contains compounds that consist of calcium, sodium, potassium, oxalate, uric acid, and phosphate . If the levels of these particles get too high, or if urine becomes too acidic or basic, the particles can clump together and crystallize. Unless the problem is addressed, the crystals will gradually grow over a few weeks, months, or even years, forming a detectable stone. Calcium oxalate is the most common type of crystal to form this way, and accounts for about 80% of kidney stones . Less common kidney stones are made of calcium phosphate , or uric acid . A slightly different t